Tracking apparatuses using radar have been used mainly for ports and large ships as well as for military purposes. In addition, the application fields of the tracking apparatuses have expanded recently to even include a field for avoiding car crashes.
The radar tracking apparatuses use α-β filters and Kalman filters, and in particular, the α-β filters are widely used for track-while-scan (TWS) tracking apparatuses that have to track tens or hundreds of targets at the same time.
The α-β filter requires much less computation than those of other tracking methods, and thus is appropriate for the TWS tracking apparatuses that have to track a plurality of targets in real-time. However, since the characteristic of measurement errors in a radar-measured value converted to a rectangular coordinate system varies with respect to the distance to and direction of a target, consideration of the characteristic is required in order to update an α-β gain.